Okuda Masahiko, Tanaka Aki, Satoh Manami, Mizuta Shoko, Takazawa Manabu, Ohkuma Yoshiaki, Nishimura Yoshifumi
Laboratory of Structural Biology, Graduate School of Supramolecular Biology, Yokohama City University, Yokohama, Japan.
EMBO J. 2008 Apr 9;27(7):1161-71. doi: 10.1038/emboj.2008.47. Epub 2008 Mar 20.
RNA polymerase II and general transcription factors (GTFs) assemble on a promoter to form a transcription preinitiation complex (PIC). Among the GTFs, TFIIE recruits TFIIH to complete the PIC formation and regulates enzymatic activities of TFIIH. However, the mode of binding between TFIIE and TFIIH is poorly understood. Here, we demonstrate the specific binding of the C-terminal acidic domain (AC-D) of the human TFIIEalpha subunit to the pleckstrin homology domain (PH-D) of the human TFIIH p62 subunit and describe the solution structures of the free and PH-D-bound forms of AC-D. Although the flexible N-terminal acidic tail from AC-D wraps around PH-D, the core domain of AC-D also interacts with PH-D. AC-D employs an entirely novel binding mode, which differs from the amphipathic helix method used by many transcriptional activators. So the binding surface between PH-D and AC-D is much broader than the specific binding surface between PH-D and the p53 acidic fragments. From our in vitro studies, we demonstrate that this interaction could be a switch to replace p53 with TFIIE on TFIIH in transcription.
RNA聚合酶II和通用转录因子（GTFs）在启动子上组装形成转录起始前复合物（PIC）。在GTFs中，TFIIE招募TFIIH以完成PIC的形成并调节TFIIH的酶活性。然而，TFIIE与TFIIH之间的结合模式尚不清楚。在这里，我们证明了人类TFIIEα亚基的C末端酸性结构域（AC-D）与人TFIIH p62亚基的普列克底物蛋白同源结构域（PH-D）的特异性结合，并描述了AC-D的游离形式和与PH-D结合形式的溶液结构。尽管来自AC-D的柔性N末端酸性尾巴围绕着PH-D，但AC-D的核心结构域也与PH-D相互作用。AC-D采用了一种全新的结合模式，这与许多转录激活因子使用的两亲性螺旋方法不同。因此，PH-D与AC-D之间的结合表面比PH-D与p53酸性片段之间的特异性结合表面要宽得多。从我们的体外研究中，我们证明这种相互作用可能是转录过程中在TFIIH上用TFIIE取代p53的一个开关。
